Ottoite

ottoite

iodargyrite

khinite

housleyite

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Formula: Pb2TeO5
Tellurate
Crystal System: Monoclinic
Specific gravity: 8.721 calculated
Streak: Pale yellow
Colour: Yellow
Solubility: Immediately decomposes in dilute hydrochloric acid, turning opaque white, expanding, and leaving an insoluble crystalline residue of PbCl2 (cotunnite).
Environments

Hydrothermal environments

Localities

There are two co-type localities, the Aga Mine and Bird Nest drift, both at Otto Mountain, Baker, Soda Mountains, Silver Lake Mining District, San Bernardino County, California, USA. At the type localities ottoite is rare and occurs on fracture surfaces and in small vugs in quartz veins. Species observed in direct association with ottoite include acanthite, bromine-rich chlorargyrite, gold, iodargyrite, khinite, wulfenite, housleyite, markcooperite, thorneite and timroseite. Other species identified in the assemblages include anglesite, atacamite, boleite, brochantite, burckhardtite, calcite, caledonite, celestine, cerussite, chalcopyrite, chrysocolla, devilline, diaboleite, fluorite, fornacite, galena, goethite, hessite, jarosite, kuranakhite, linarite, malachite, mimetite, mottramite, munakataite, murdochite, muscovite, perite, phosphohedyphane, plumbojarosite, pyrite, schieffelinite, vanadinite, vauquelinite, paratimroseite and telluroperite.
It is inferred that the secondary tellurium minerals, as well as the other secondary minerals, formed in a multitude of local micro-environments that resulted from the partial oxidation of the primary sulphides during or following brecciation of the veins. The tellurium would have been provided by the oxidation of hessite and perhaps other, as yet unrecognised, tellurides. The later generation of quartz mineralisation then recemented the breccia, effectively isolating and protecting from further alteration the delicate secondary minerals, as well as the remaining sulphides (AM 95.8.1329-1336).

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